They are reversed in Steam VR too. I use a model that shows L/R on the front.
Mostly though, it usually works if I raise the left hand first in SteamVR, after reversing the tracking direction in Leap.
It would be cool if there was some kind of switch controller button in Driver4VR though, would that be a possibility?
For now though it works well enough, you can ignore most of that above. The poor tracking was the main problem, and the workaround works every time.